JPS62133070A - Device for forming cvd (chemical vapor deposited) thin film - Google Patents

Abstract

PURPOSE:To effectively prevent the fine grain of a generating foreign material from being stuck on the surface of a wafer by providing concentrically three pieces of nozzles wherein the tips are projected in accordance with proceeding toward an outside and introducing gaseous N2 through an outer most side nozzle and joining a conical cover to the terminal of a curve-shaped outer periphery thereof. CONSTITUTION:In a device forming a CVD (chemical vapor deposited) thin film, the first nozzle 10, the second nozzle 20 and the third nozzle 30 are concentrically provided near to the vertex of a conical cover 40. The tip part 21 of the second nozzle 20 is projected in comparison with the tip part 11 of the first nozzle 10 and the tip part 31 of the third nozzle 30 is projected in comparison with the tip part 21 of the second nozzle 20 and the top fitting base part of the conical cover 40 of a reaction furnace is joined along the outer peripheral terminal 32 of the curve-shaped inner wall surface of the third nozzle 30. The thin film is formed on a wafer by introducing a reaction gas through the first nozzle 10 and the second nozzle 20 and introducing gaseous N2 through the third nozzle 30. Thereby the fine grains of a foreign material can be prevented from being stuck on the surface of the wafer and the yield is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a CV l) thin film forming apparatus. More specifically, the present invention relates to a CVD thin film forming apparatus having a large reactant gas nozzle to which substances such as SiO2 particles are difficult to adhere.

[Prior Art] One of the methods widely used in the 7B conductor industry as a method for forming thin films is vapor phase epitaxy (CVI).
:Chemical Val)ourl)epos
There is an i t i on). CVD refers to turning a gaseous substance into a solid substance through a chemical reaction and depositing it on a substrate.

The characteristics of CV I) are that various thin films can be obtained at deposition temperatures considerably lower than the melting point of the thin film to be grown, and that the purity of the grown thin films is high, and the thermal oxide film of Si and Si Because it has stable electrical properties even when grown, it is widely used as a passivation film on semiconductor surfaces.

Thin film formation by CV I) is performed by, for example, injecting a reactive gas (for example, 5iHq+02.
or S i Hq +PH3+02). 1. The reaction gas described above is blown onto a wafer in a reactor (belljar) using N2 gas as a carrier, and a thin film of, for example, SiO2 or phosphosilicate glass (PSG) is formed on the surface of the wafer. Also, Si
Two-phase film formation of O2 and PSG is sometimes performed.

An example of an apparatus conventionally used for carrying out such a thin film forming operation using CV I) is shown in FIG. 2 as a partial cross-sectional view.

In FIG. 2, a reactor (bell jar) 1 has a conical buffer 2 covered with a conical cover 3, and a ring-shaped wafer mounting table 4 that can be rotated or rotated around the buffer 2. It is installed in

Reaction gas feed pipes 8 and 9 are connected near the apex of the conical cover 3. 8a and 9a are large reaction gas feeding nozzles, respectively. 5iHq and 0 of the reaction gas used
2 must be fed into the reactor through separate gas feed pipes. For example, S i H4 is fed through the feed pipe 8, and 02 is fed through the feed pipe 9. If PHa is used, it can be delivered with 5iHq. These reaction gases are generally diluted with N2 gas to an appropriate concentration and fed to the reactor.

A heater 10 is provided directly below the wafer mounting table 4 with a slight gap therebetween, and a heater 10 is installed to hold the wafer 5 in a predetermined position. +
Heat to A degree (eg 500°C). The reaction gas (for example, 5iHq+
02 or S iHq+PH3+02), arrow a,
a', b, b'Nokoto<flow inside the reactor,
Touch the surface of the wafer 5 and apply a thin film of a substance (for example, SiO2 or PSG) generated by a chemical reaction to the wafer 5.
adhere to the surface of the

[Problems to be Solved by the Invention] However, with this device, as shown in FIG. is also outstanding. Furthermore, the tip of the reaction gas feed nozzle 9a on the outer peripheral side protrudes beyond the mounting base of the conical cover.

As a result, while performing 7471 on a 5i02 thin film on a wafer, the reaction gas SiH4 and 02 reacted at the protruding part of the nozzle, generating fine particles of 5i02, which tended to adhere to the protruding part of the nozzle. . Historically, the reaction gas stays in the fibrous annular space 12 formed by the outer reaction gas large nozzle 9a and the conical cover 3, and a large number of 5i02@ particles are generated and adhered to the wall surface of this space.

These adhered fine particles are blown away when the reaction gas is ejected, or peeled off by slight vibrations.

Some of them fall directly onto the wafer surface and adhere to them, while others float in the furnace. Large suspended particles gradually begin to settle and fall onto the wafer surface. On the other hand, small suspended particles continue to float in the furnace for a long time, and some of them become agglomerated (C
The particles form large particles and settle toward the wafer surface. The other part adheres to the furnace wall and forms a kind of flake. These flakes may fall off due to slight vibration or wind pressure and may fall and adhere to the wafer surface I.

When these particles (7d particles) adhere to the wafer, they cause pinholes in the deposited film, resulting in a drawback that the manufacturing yield of conductor elements is significantly lowered.

Therefore, the first object of the present invention is to provide a CVl thin film forming apparatus in which oxide particles are less likely to be generated or adhered to the reaction gas feeding nozzle portion.

[Means for Solving the Problems 11] As a means for solving the problems described in 1., the present invention provides the following. Second. A third nozzle is arranged concentrically with the first nozzle. Second. The third nozzle is the first, second, and so on. Third
The reactant gas is fed through the first and second nozzles, the N2 gas is fed through the third nozzle, and the inner peripheral wall surface of the third nozzle has a curved line having a predetermined curvature. A CVD thin film forming apparatus is provided, characterized in that the CVD thin film forming apparatus is formed in a curved shape, and a one-way mounting base of a conical cover of a reactor is connected along the outer peripheral end of the curved shape.

[Operations] As described above, in the CV I) thin film forming apparatus of the present invention, the first. Second. The third nozzle is the first nozzle. Since it is disposed protruding from the second and third rlIn, the surface of the tip of the first nozzle is always washed by the gas sent from the second nozzle, making it difficult for foreign particles to adhere.

Similarly, the surface of the tip of the second nozzle is constantly washed by the N2 gas sent from the third nozzle, making it difficult for foreign particles to adhere to it.

The lower inner peripheral wall surface of the third nozzle is formed into a curved shape having a predetermined curvature, and the E-numbered base of the conical cover of the reactor is joined along the outer peripheral end of the curved shape. As a result, the lower inner circumferential wall surface of the third nozzle is constantly washed with N2 gas, so that foreign particles are less likely to adhere to this part.

In addition, the reaction gas sent from the nozzle does not stagnate anywhere in the nozzle attachment part (the curved inner peripheral wall surface of the third nozzle, the circle XF that continues to this curve, and the inner wall surface of the cane cover). It flows down the furnace in a laminar state and reaches the wafer on the wafer mounting table.

As a result, foreign particles such as 5i02 and the like generated and attached to the nozzle portion can be completely eliminated.

Therefore, the inconvenient situation where these foreign particles fall onto the wafer surface and cause pinholes in the deposited film can be effectively prevented, and the production of the conductor elements can be effectively prevented. The yield can be improved by 1.

[Embodiment Code] Referring to the drawings, one embodiment of the present invention will be described in detail below.

FIG. 1 is an enlarged sectional view of the nozzle portion of the CV l) thin film forming apparatus of the present invention.

As shown in FIG. 1, the nozzle portion in the CVD thin film forming apparatus of the present invention is the first. Second. and third nozzles 10, 20, 30 are arranged concentrically near the top of the conical cover 40 of the reactor.

The tip 21 of the second nozzle 20 protrudes more than the tip 11 of the first nozzle 10. Further, the tip 31 of the third nozzle 30 protrudes more than the tip 21 of the second nozzle 20.

The first nozzle and the second nozzle are used for feeding the reaction gas, and the third nozzle is used for feeding the N2 gas. The first nozzle is, for example, S 1Htt (sometimes PHa
), and the second nozzle is, for example,
Used for supplying 02 gas. However, the reverse can also be implemented. Also, other reactive gases may be used instead of 02, such as N
20. CO2゜NHJ etc. can also be used. Furthermore, impurities such as B2 H6 and AsH3 can also be used instead of PH3. Such reactant gas combinations are well known to those skilled in the art.

The reaction gas can also be supplied diluted with N2 gas.

As mentioned above, the first. Second. The third nozzle is the first and second nozzle.
．． Since the first nozzle 10 is arranged to protrude in the third order, the first nozzle 10
The surface of the tip 11 of the tip 11 is constantly washed by the gas sent from the second nozzle, making it difficult for foreign particles to adhere to it. Similarly, the second
The tip portion 21 of the nozzle 20 receives N supplied from the third nozzle.
The surface is constantly washed by the two gases, making it difficult for foreign particles to adhere.

The lower inner peripheral wall surface of the third nozzle is formed into a curved shape having a predetermined curvature, and the upper mounting base 41 of the conical cover 40 of the reactor is joined along the outer peripheral end 32 of the curved shape. As a result, the inner peripheral wall surface of the third nozzle is N2
Since it is constantly washed with gas, it is rare for foreign particles to form or adhere to this area. In addition, the gas sent from the nozzle does not stagnate anywhere in the nozzle attachment part (it flows laminarly along the curved inner peripheral wall surface of the third nozzle and the inner wall surface of the conical cover that continues from this curve). In this state, the wafer flows through the furnace and reaches the wafer on the wafer mounting table.

In order to prevent foreign matter from adhering, it is preferable that the tip 11 of the first nozzle 10 and the tip 21 of the second nozzle 20 also be chamfered to remove acute angle portions.

The nozzle structure as described above can be applied to all types of CV I) reactors in which the reaction gas is introduced from the upper part of the reactor. This type of CVD reactor is disclosed, for example, in Japanese Patent Application No. 60-34555.

[Effects of the Invention] As described in 1. below, in the CV l) thin film forming apparatus of the present invention, 1. Second. The third nozzle is the first, second, and so on. Since they are arranged in a protruding manner in the third order, the surface of the tip of the first nozzle is always scratched by the gas sent from the second nozzle, making it difficult for foreign particles to adhere thereto. Similarly, the surface of the tip of the second nozzle is constantly washed by the N2 supplied from the third nozzle, making it difficult to apply Mt.

The lower peripheral wall surface of the third nozzle is formed into a curved shape with a predetermined curvature, and the base of one part of the conical cover of the reactor is joined along the outer peripheral end of the curved shape. As a result, the lower circumferential wall surface of the third nozzle is constantly washed with N2 gas, so foreign matter is less likely to occur or adhere to this portion.

In addition, the reaction gas sent from the nozzle does not stay anywhere in the nozzle attachment part, and is layered along the curved inner circumferential wall surface of the third nozzle and the inner wall surface of the 11111-shaped cover that continues from this curve. The liquid flows through the furnace in a flowing state and reaches the wafer on the wafer mounting table l-.

As a result, all the foreign particles -r- such as 5i02 etc. generated and attached to the nozzle part are removed! ;(can be.

Therefore, the inconvenient situation in which these foreign particles fall onto the wafer surface and cause pinholes in the vapor 7 film can be effectively prevented from raining.
The production yield can be improved by 1-.

Another effect of the present invention is that the nozzle structure as described above is suitable for use in a type of CV that feeds reaction gas from a part of the reactor 1.
I) It can be applied to all reactors, so the range of application is extremely wide.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of the nozzle portion of the CVD thin film forming apparatus of the present invention. FIG. 2 is a partial sectional view of an example of a conventional CVD thin film forming apparatus. 10... First nozzle 11... First nozzle tip 2
0... Second nozzle 21... Second nozzle tip 30
...Third nozzle 31...Third nozzle tip 32.
...Third nozzle curved inner peripheral wall and outer peripheral end 40...Reactor conical cover

Claims (2)

[Claims] (1) The first, second, and third nozzles are arranged concentrically, and the first, second, and third nozzles are arranged to protrude in the order of the first, second, and third nozzles. , the reaction gas is fed from the first and second nozzles, the N_2 gas is fed from the third nozzle, and the lower peripheral wall surface of the third nozzle is formed in a curved shape having a predetermined curvature. . A CVD thin film forming apparatus, characterized in that an upper mounting base of a conical cover of the reactor is joined along the outer peripheral end of the curved shape. (2) The first and second nozzles are for feeding reaction gas,
The CVD thin film forming apparatus according to claim 1, wherein the third nozzle is for feeding N_2 gas.